Pythonomorpha was originally proposed by paleontologist Edward Drinker Cope (1869) as a reptilian order comprising snakes and mosasaurs. The etymology of the term Pythonomorpha comes from the Greek Python (a monstrous snake from Greek mythology) and morphe ("form"), and refers to the generally serpentine body plan of members of the group. Cope wrote, "In the mosasauroids, we almost realize the fictions of snake-like dragons and sea-serpents, in which men have been ever prone to indulge.